Analuddin Kangkuso, Suwa Rempei, Hagihara Akio
Graduate School of Engineering and Science, University of the Ryukyus, Okinawa 903-0213, Japan.
J Plant Res. 2009 Jan;122(1):53-9. doi: 10.1007/s10265-008-0190-8. Epub 2008 Nov 13.
The self-thinning process was monitored in crowded Kandelia obovata Sheue, Liu & Yong stands over four years. The frequency distribution of tree phytomass was an L-shape, which was kept over the experimental period. Spearman's rank correlation coefficient for phytomass decreased as the time span of the comparison became longer, a result which indicates that the rank of phytomass changes as stands grow. Death of trees resulted from one-sided competition, i.e., death occurred in lower-rank trees. Surviving trees continued to grow. Whatever the current spatial distribution of the trees, death occurred randomly and the spatial distribution gradually became close to random as stands grew. The self-thinning exponent was 1.46, which can be regarded as evidence in favor of the 3/2 power law of self-thinning. Relative growth rate, RGR, decreased in proportion to decreasing relative mortality rate, RMR, with a proportionality constant of 1.57, which was not significantly different from the slope of the self-thinning exponent. This experimental result probably justifies the assumption that the ratio of RGR to RMR in the mean phytomass-density trajectory for any self-thinning population with different densities becomes constant as the growth stage progresses.
在四年时间里，对生长密集的海桑（Kandelia obovata Sheue, Liu & Yong）林分的自疏过程进行了监测。树木植株生物量的频率分布呈L形，在整个试验期内保持不变。随着比较时间跨度的延长，生物量的斯皮尔曼等级相关系数降低，这一结果表明生物量的等级随林分生长而变化。树木死亡是由单侧竞争导致的，即较低等级的树木死亡。存活的树木继续生长。无论树木当前的空间分布如何，死亡都是随机发生的，并且随着林分生长，空间分布逐渐接近随机分布。自疏指数为1.46，这可被视为支持自疏3/2幂律的证据。相对生长率（RGR）与相对死亡率（RMR）的降低成比例下降，比例常数为1.57，这与自疏指数的斜率没有显著差异。这一实验结果可能证明了这样一个假设：对于任何具有不同密度的自疏种群，随着生长阶段的推进，平均植株生物量 - 密度轨迹中RGR与RMR的比值会变得恒定。
